CXXXll PROCEEDINGS OF THE GEOLOGICAL SOCIETY. 



miles the depth is only 300 fathoms, so that a ridge rises here 

 with a slope very steep on the inshore side and a little less seaward ; 

 this ridge is 1500 feet above a hollow seaward of it, and twelve miles 

 distant ; in another twelve miles there is again a rise of 500 feet, on 

 a base of twelve miles, which is followed by a depression of 300 feet 

 on a base of fifteen miles, and then by a gentle slope upwards with 

 only very moderate variations. The lines of equal temperature follow 

 these bends in the sea-bottom, the line of 57° of temperature sinking 

 down in the deep hollow before noticed to a depth of 600 fathoms, 

 and rising up over the ridge to the depth of 220 fathoms. These 

 variations are curious, as they show that the cold water does not 

 maintain a level surface, but follows the inequalities of the sea-bottom, 

 lifting up or lowering down the warm Gulf-stream above it; and it is 

 easy to perceive how the progression of animal life may be affected 

 by such circumstances. In this section, the temperature at 175 

 nautical miles is 11'^, which does not descend lower than 20 or 

 25 fathoms ; the temperature of 72° to about Ih fathoms ; that of 

 ^1° to 200; and of 62° to 300 fathoms; these several zones stretching- 

 out in a similar manner laterally. 



Mr. Poole, on behalf of the Government, visited the Dead Sea, and 

 the Society has to thank the Foreign Office for communicating in this 

 and in many other cases the information obtained. The object of Mr. 

 Poole was to ascertain whether nitre could be obtained, as reported, 

 in large quantities, but he found none, common salt having been ap- 

 parently confounded with it from a similarity in the Arabic names for 

 the two salts ; sulphur, sulphurous earths, and common salt are the 

 products of the district. Several reports on the Eruption of Mauna 

 Loa in Hawaii came to us from Consul-general Miller, also through 

 the Foreign Office. This eruption was remarkable for the height 

 of the mountain, 14,000 feet ; for the time during which the current 

 of lava continued to flow, about three months ; for the distance over 

 which it passed, fifty miles ; and from the fact that the lava flowed 

 underground for a considerable distance. 



From Mr. Babbage we have had an ingenious explanation of the 

 manner in which the detritic matter carried down by streams is dis- 

 tributed in tiie ocean, being carried forward by the velocity acquired 

 by the river-water in its descent u})on land and drawn downward by 

 gravity, but slowly, in consequence of the resistance of the medium. 

 The action of currents modifies the direction of the moving matter, 

 which in this way forms a film or plane of mud or other detritus, 

 gradually sinking downwards, and, in Mr. Babbage' s opinion, occa- 

 sionally capping the rocks below and producing the appearance of 

 outliers. Without doubt the descent of detritus must be conducted 

 in something like the manner here described, subject to the dis- 

 turbing action of storms and currents ; it was Mr. Babbage's object 

 to trace the progress of the descent, and to speculate upon the con- 

 sequent formation of strata, which he has done with his usual 

 ingenuity. 



After an interval of thirty years, Mr. Poulett Scrope has again 

 brought before geologists his views on the formation of craters and 



